Fitech running fat

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Devo44

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LONG story ill try to be short. 496 bbc .585 hyd roller cam alum ported chevy heads edelbrock rpm air gap tko 600 9" 3.70 gear ran great with qf 850 carb. switched to fitech 800 mean street. new fuel tank w/400lph pump bypass regulator at 43psi. cant get it to lean out no matter what. back fire and popping randomly at idle, no power when I step on it. plugs (e3) carbon fouled. msd 6al2, hei, accel coil 13* initial 32 total. called fitech twice said I had emi trouble or exhaust leak. emi would show fault code, but no fault code. no exhaust leak. so both techs I talked to said "I don't know what else it could be, sorry" REALLY! I have read a ton of tech tips and tried A LOT of different things to try and lean it out. compression 180 in all 8. set and reset valves 5 times. pulled and checked all valvetrain no broken valve springs. no bent pushrods. all rockers in good shape. anybody got a guess why this is untuneably rich? Think I just made up a word. thanks.
 
Just a random shot in the dark but check the egr valve and the pcv to make sure its not something simple
 
I never seen anyone use a bypass regulator on a fitech it has its own built into it along with its own return and I think it requires over 50psi fuel pressure .
 
Don't know much about the Fitech, I have the Fast. It has a section in the controller to set the air to fuel ratio for idle, cruise and wot. Then there is a screen for live settings as the car runs.
Like Big says check the mechanicals first. good luck
 
Your first post on a Mopar website is asking about a problem on a BBC? Man, you must be desperate for help. Welcome to FABO!
 
The FiTech has a setup screen that allows for the basic engine parameters to be set also. To include AFR and Engine Cubes which will affect the fuel ratio.
 
jimjimjimmy said:
I never seen anyone use a bypass regulator on a fitech it has its own built into it along with its own return and I think it requires over 50psi fuel pressure .
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Yes the tech guy at fitech said the internal regulator is only capable of suppressing 340lph pumps. Mine is 400 so he said to bypass regulate it down to 43-46lbs.
 
mario03srt said:
The FiTech has a setup screen that allows for the basic engine parameters to be set also. To include AFR and Engine Cubes which will affect the fuel ratio.
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Ya all that has been done, reset and redone several times
 
Idle and Part throttle could be at that AFR and that's perfectly fine. A tad rich but still ok. 14.7 AFR is the optimum for emissions at those throttle positions. 13.9 is ok and you will not notice any issues. On your ride you want to be at 12.7 max or so at Wide Open Throttle. The system will make the changes as you go from closed to open loop in the fuel table. Anything less than 80% throttle (TPS controlled) is closed loop, over 80% there is a different fuel and timing table for Oh **** Mode! Look at your TPS readings on the screen and the corresponding AFR.

Marion
 
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Ok but that's not a rich AFR. Recheck the WB sensor, where is it located on the exhaust and what clock position is it at? It could be goobered up maybe. It must be airtight and the sensor itself clean and away from any water /moisture in the ex stream.
 
mario03srt said:
Ok but that's not a rich AFR. Recheck the WB sensor, where is it located on the exhaust and what clock position is it at? It could be goobered up maybe. It must be airtight and the sensor itself clean and away from any water /moisture in the ex stream.
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Yes its clocked correct i even removed and cleaned it. Dizzy is not controlled by efi unit.
 
Devo44 said:
I believe it was around 12.9
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Devo,

Ok so the unit says that it is not running rich. ;) But the plugs say maybe so and the way it runs also maybe.

Do the 2 AFR setting values coincide with the readouts? 13.9 = 13.9 +/- a skosh or is it 13.1 = 13.9? Also WOT. So to try and be sure, go into the controller and adjust the AFR at idle to a lower or higher value and see the readout results.

Also as a check see what the % fuel trim is at idle on the controller, mine is about -29% as it sets.
 
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